From: Daniel Baird <danielbaird@...>
Date: 2006-03-22T18:34:58+09:00
Subject: Re: Is this a kind of design patterns?

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The truth is, as a ganeral rule the original G4 design patterns were kinda
statically-typed-language-centric, so it wouldn't surprise me if there was
some small details in Ruby versions of the patterns that didn't quite fit
the "classic" description.

In this case though, it does look a lot like the Factory pattern, apart fro=
m
new still being available.  I think if Color.new was re-declared as private=
,
that would make it a textbook case of the Factory pattern.

IANA(language)L though..

;Daniel

On 22/03/06, killy-kun <killy-kun@wanadoo.fr> wrote:
>
> Sam Kong wrote:
> > Hi!
> >
> > Sometimes a class provides object instantiation methods other than new.
> > See an example.
> >
> > class Color
> >     def initialize r, g, b
> >         @r =3D r
> >         @g =3D g
> >         @b =3D b
> >     end
> >
> >     def to_s
> >         "R: #{@r}, G: #{@g}, B: #{@b}"
> >     end
> >
> >     class << self
> >         def red
> >             new 255, 0, 0
> >         end
> >
> >         def blue
> >             new 0, 0, 255
> >         end
> >
> >         def green
> >             new 0, 255, 0
> >         end
> >     end
> > end
> >
> > puts Color.new(100, 120, 140)
> > puts Color.red
> > puts Color.blue
> >
> >
> > Is this one of design patterns, or just a simple idiom?
> > It's similar to a factory method pattern but it's not according to the
> > definition.
> > Is there any name for it?
> >
> > TIA.
> >
> > Sam
> >
>
> isn't that the facory design pattern ?
>
>


--
Daniel Baird
http://danielbaird.com (TiddlyW;nks! :: Whiteboard Koala :: Blog :: Things
That Suck)
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